KR101181040B1 - Use of cl2 and/or hcl during silicon epitaxial film formation - Google Patents

Abstract

In one aspect of the invention, a first method of forming an epitaxial film on a substrate is provided. The first method comprises (a) providing a substrate; (b) exposing the substrate to at least one silicon source such that an epitaxial film is formed on at least a portion of the substrate; And (c) exposing the substrate to HCl and Cl ₂ such that the epitaxial film and any other films formed during step (b) are etched. Various other aspects are provided.

Description

Use of C2 and / or HCl during formation of silicon epitaxial film {USE OF CL2 AND / OR HCL DURING SILICON EPITAXIAL FILM FORMATION}

This application claims priority to US patent application Ser. No. 11 / 001,774 (Doct. No. 9618), filed Dec. 1, 2004, and is a Continuation-in-part of the U.S. patent application, September 2005. Claim priority of US patent application Ser. No. 11 / 227,974, filed on 14 December. Each of the above applications is hereby incorporated by reference in its entirety.

Embodiments of the present invention generally relate to the field of electronic manufacturing processes and devices, and more particularly to methods of depositing silicon-containing films while forming electronic devices.

As transistors are made smaller, the manufacture of extremely shallow source / drain junctions becomes more important. Generally, sub-100 nm CMOS (complementary metal-oxide semiconductor) devices require a junction depth of less than 30 nm. Selective epitaxial deposition is sometimes used to form epilayers of silicon-containing materials (eg, Si, SiGe and SiC) in the junction. In general, selective epitaxial deposition allows epilayer growth on silicon moats without growth on dielectric regions. Selective epitaxy is used in semiconductor devices such as elevated source / drain, source / drain extensions, contact plugs or base layer deposition of bipolar devices.

In general, selective epitaxy processes involve deposition reactions and etching reactions. Deposition and etching reactions occur simultaneously at relatively different reaction rates for the epitaxial and polycrystalline layers. During the deposition process, the epitaxial layer is formed on the monocrystalline surface while the polycrystalline layer is deposited on at least a second layer, such as a conventional polycrystalline layer and / or amorphous layer. However, the deposited polycrystalline layer is generally etched at a faster rate than the epitaxial layer. Thus, by varying the concentration of etchant gas, the net selective process results in the deposition of epitaxial material and does not cause the deposition of polycrystalline material or the deposition of polycrystalline material. For example, a selective epitaxy process may form an epilayer of silicon-containing material on the monocrystalline silicon surface while leaving no deposition on the spacers.

Selective epitaxy deposition of silicon-containing materials during formation of raised source / drain and source / drain extension features, eg, during formation of a silicon-containing MOSFET (metal oxide semiconductor field effect transistor) device Has become a useful technique. Source / drain extension features are fabricated by etching the silicon surface to create a recessed source / drain feature and sequentially filling the etched surface with selectively grown epi layers, such as silicon germanium (SiGe) material. Selective epitaxy allows nearly complete doping activation with in-situ doping so that the post annealing process is omitted. Thus, junction depth can be accurately formed by silicon etching and selective epitaxy. On the other hand, extremely shallow source / drain junctions inevitably result in increased series resistance. In addition, the junction reduction increases the series resistance even further during silicide formation. To compensate for junction reduction, raised sources / drains are selectively grown epitaxially on the junction. Typically, the raised source / drain layer is undoped silicon.

However, current selective epitaxy processes have some drawbacks. In order to maintain selectivity during the provided epitaxy process, the chemical concentration and reaction temperature of the precursors must be controlled and controlled throughout the deposition process. If not enough silicon precursor is introduced, the etching reaction prevails and the entire process is delayed. In addition, undesirable overetching of substrate features may occur. If insufficient etchant precursor is introduced, the deposition reaction may prevail and the selectivity may be reduced in forming monocrystalline and polycrystalline materials across the substrate surface. In addition, current selective epitaxy processes typically require high reaction temperatures of about 800 ° C, 1000 ° C or more. Such high temperatures are undesirable during the manufacturing process due to thermal budget considerations and uncontrolled nitriding reactions on the substrate surface.

Therefore, a process for selectively and epitaxially depositing silicon and silicon-containing compounds with selective dopants is desired. In addition, the process should be flexible to form silicon-containing compounds having varying element concentrations while having a fast deposition rate and maintaining process temperatures of about 800 ° C. or less, preferably about 700 ° C. or less.

In one aspect of the present invention, a first method of forming an epitaxial film on a substrate is provided. The first method comprises (a) providing a substrate; (b) exposing the substrate to at least a silicon source to form an epitaxial film on at least a portion of the substrate; And (c) exposing the substrate to HCl and Cl ₂ to etch any other films and epitaxial films formed during step (b).

In two aspects of the present invention, a second method of forming an epitaxial film on a substrate is provided. The second method comprises (a) providing a substrate; (b) exposing the substrate to a silicon source and a carbon source to form a carbon-containing silicon epitaxial film; (c) encapsulating the carbon-containing silicon epitaxial film with the encapsulation film; And (d) exposing the substrate to Cl ₂ to etch the encapsulation film.

In a third aspect of the present invention, a method of forming an epitaxial film on a substrate is provided. The third method comprises (a) providing a substrate; (b) exposing the substrate to a silicon source and an additional element source to form an additional element containing silicon epitaxial film; (c) encapsulating the additional element-containing silicon epitaxial film with the encapsulation film; And (d) exposing the substrate to Cl ₂ to etch the encapsulation film. Various other aspects are provided in accordance with the above and other embodiments of the present invention.

Other features and aspects of the present invention will be more clearly understood with reference to the following detailed description, appended claims and drawings.

DETAILED DESCRIPTION In order to understand the above-mentioned features of the present invention through a more detailed description of the present invention, the above brief description, reference is made to several embodiments shown in the accompanying drawings. However, the accompanying drawings show only typical embodiments of the present invention, but are not intended to limit the scope of the present invention, the present invention may implement other equivalent embodiments.

1 is a flow diagram illustrating a process for selectively epitaxially depositing a silicon-containing material in at least one embodiment disclosed herein.

2A-2E are schematic diagrams of fabrication techniques for source / drain extension devices in MOSFETs.

3A-3C illustrate several devices including optionally epitaxially deposited silicon-containing layers applied to embodiments described herein.

4 is a flow diagram illustrating a process for selectively epitaxially depositing a silicon-containing material in another embodiment disclosed herein.

5 is a flow chart of a first method of using Cl ₂ while forming a silicon epitaxial film in accordance with the present invention.

6 is a flow chart of a second method of using Cl ₂ while forming a silicon epitaxial film in accordance with the present invention.

7 is a flow chart of a third method of using Cl ₂ while forming a silicon epitaxial film in accordance with the present invention.

8 is a flow chart of a fourth method of using Cl ₂ while forming a silicon epitaxial film in accordance with the present invention.

9 is a block diagram of an exemplary epitaxial film formation system provided in accordance with the present invention.

Carbon injection into silicon epitaxial films can yield useful electrical properties, such as improving the electrical properties of the channel of a metal oxide semiconductor field effect transistor (MOSFET). However, this useful electrical performance is achieved when carbon is integrated substitutionally rather than interstitially and integrated in the silicon lattice. At substrate processing temperatures of about 600 ° C. or less, most of the carbon atoms are integrated into the silicon lattice during the epitaxial formation process. At higher substrate temperatures, such as at least about 700 ° C., significant intercalation carbon integration can be achieved. For this reason, when forming a carbon-containing silicon epitaxial film, it is preferable to use a substrate temperature lower than about 700 ° C, more preferably lower than about 600 ° C.

Conventional silicon epitaxial film formation processes employ silicon sources such as H ₂ , HCl and dichlorosilane and are performed at substrate temperatures above about 700 ° C. (eg to decompose HCl and / or silicon sources). One way to reduce the epitaxial film formation temperature is to use Cl ₂ instead of HCl as Cl ₂ is efficiently decomposed at lower temperatures (eg, about 600 ° C. or less). Because of the incompatibility between hydrogen and Cl ₂ , a carrier gas other than hydrogen, such as nitrogen, may be used with Cl ₂ . Similarly, silicon sources with low decomposition temperatures (eg silanes, disilanes, etc.) may be used.

The inventors have found that the use of Cl ₂ as an etchant gas for a silicon epitaxial film formation process It has been found that the surface morphology of the formed silicon epitaxial film can be deteriorated. Without wishing to be bound to any particular theory, it is believed that Cl ₂ can over attack the silicon epitaxial film surface, forming pitting and the like. The use of Cl ₂ has been found to be particularly problematic when the silicon epitaxial film contains carbon.

The present invention provides a method of using Cl ₂ as an etchant gas during a silicon epitaxial film formation process that can improve epitaxial film surface morphology. The process of the present invention is described, for example, by the selective gas supply (AGS, disclosed below) with reference to parent application US patent application Ser. No. 11 / 001,774 filed on Dec. 1-4 and Dec. 1, 2004 (Doc. No. 9618). You can use an alternating gas supply process.

In some embodiments disclosed below with reference to FIG. 5, both Cl ₂ and HCl are used during the etching step of the silicon epitaxial film formation process. The presence of HCl is shown to reduce the aggressiveness of Cl ₂ even at reduced substrate temperatures (eg, below about 600 ° C.) where HCl hardly decomposes. In addition, during the AGS process, HCl may be continuously introduced during the deposition and etching steps of the process (eg, to improve surface morphology), as described below with reference to FIG. 6.

As disclosed above, the use of a carbon-containing silicon epitaxial film and Cl ₂ may produce an epitaxial film with poor surface morphology (eg, fitting). In some embodiments disclosed below with reference to FIG. 7, any carbon-containing silicon epitaxial film may be “encapsulated” prior to exposure to Cl ₂ during the etching step. The carbon-containing silicon epitaxial film may be encapsulated through a silicon epitaxial film ("non-carbon containing silicon epitaxial film") formed, for example, without using a carbon source, as described below with reference to FIG. 8. Can be. These and other embodiments of the invention are disclosed below.

Optional gas supply Epitaxial film  Forming process

The parent application US patent application Ser. No. 11 / 001,774 filed Dec. 1, 2004 (Doct. No. 9618) generally selectively epitaxially deposits a silicon-containing material on a monocrystalline surface of a substrate during the manufacture of an electronic device. Provide a process to do this. A patterned substrate comprising a monocrystalline surface (eg silicon or silicon germanium) and at least a secondary surface such as an amorphous surface and / or a polycrystalline surface (eg oxide or nitride) is exposed to an epitaxial process Thereby forming an epitaxial layer on the monocrystalline surface while limiting or preventing the formation of the polycrystalline layer on the secondary surface. An epitaxial process, also called an selective gas supply (AGS) process, includes repeating the deposition process and etching process cycles until an epitaxial layer of desired thickness is grown.

The deposition process includes exposing the substrate surface to a deposition gas containing at least a silicon source and a carrier gas. The deposition gas may also include a germanium source or a carbon source and a dopant source. During the deposition process, an epitaxial layer is formed on the monocrystalline surface of the substrate and the polycrystalline layer is formed on a secondary surface, such as an amorphous and / or polycrystalline surface. In turn, the substrate is exposed to the etching gas. Etching gases include etchant and carrier gases such as chlorine gas or hydrogen chloride. The etch gas removes silicon-containing material deposited during the deposition process. During the etching process, the polycrystalline layer is removed at a faster rate than the epitaxial layer. Thus, the final result of the deposition and etching process forms epitaxially grown silicon-containing material on the monocrystalline surface while minimizing the growth of the polycrystalline silicon-containing material on the secondary surface. The cycle of the deposition and etching process may be repeated as required to obtain a silicon-containing material of the desired thickness. Silicon-containing materials that may be deposited according to embodiments of the present invention include silicon, silicon germanium, silicon carbon, silicon germanium carbon, and dopant variants thereof.

In one example of an AGS processor, the use of chlorine gas as an etchant lowers the overall process temperature below about 800 ° C. In general, the deposition process can be performed at a lower temperature than the etching reaction, because the etchant requires a high temperature to be activated. For example, silane can be thermally decomposed to deposit silicon below about 500 ° C., and hydrogen chloride requires an active temperature of about 700 ° C. or higher to act as an effective etchant. Thus, when hydrogen chloride is used during the AGS process, the overall process temperature is set according to the higher temperature required for the etchant to be activated. Chlorine contributes to the overall AGS process by reducing the overall process temperature required. Chlorine may be activated at a low temperature of about 500 ° C. Thus, by incorporating chlorine as an etchant into the AGS process, the overall AGS process temperature can be reduced by as much as 200 ° C. to 300 ° C. as compared to processes using hydrogen chloride as an etchant. In addition, chlorine etches silicon-containing materials faster than hydrogen chloride. Thus, chlorine etchant increases the overall speed of the AGS process.

In another example of an AGS process, an inert gas such as nitrogen is used as the carrier gas during the deposition and etching process instead of a conventional carrier gas such as hydrogen. The use of inert carrier gas has several characteristics during the AGS process. For example, the inert carrier gas can increase the deposition rate of the silicon-containing material. Although hydrogen can be used as the carrier gas during the deposition process, hydrogen tends to be absorbed or react with the substrate to form a hydrogen-terminated surface. Hydrogen-terminated surfaces have a much slower epitaxial growth than bare silicon surfaces. Thus, the use of an inert carrier gas does not adversely affect the deposition reaction, increasing the deposition rate.

Although rare gases such as argon or helium can be used as the inert carrier gas, nitrogen is the economically preferred inert carrier gas. In general, nitrogen is much cheaper than hydrogen, argon or helium. One of the problems that can be caused by using nitrogen as the carrier gas is the nitriding of the material on the substrate during the deposition process. However, in order to activate nitrogen in this manner, a high temperature of 800 ° C. or higher is required. Therefore, nitrogen is preferably used as an inert carrier gas in AGS processes carried out at temperatures below the nitrogen activation limit. The combined effect of using chlorine as an etchant and nitrogen as a carrier gas significantly increases the speed of the overall AGS process.

Throughout this specification, the terms 'silicon-containing' material, compound, film or layer should be configured to include compositions containing at least silicon and include germanium, carbon, boron, arsenic, phosphorus gallium and / or aluminum It may include. Other elements such as metals, halogens or hydrogen may be incorporated in silicon-containing materials, compounds, films or layers, typically at parts per million (ppm) concentrations. Compounds or alloys of silicon-containing materials may be represented by abbreviations such as Si for silicon, SiGe for silicon germanium, SiC for silicon carbon, and SiGeC for silicon germanium carbon. These abbreviations do not refer to chemical equations with stoichiometric relationships or any particular reduction / oxidation state of silicon-containing materials.

1 shows an example of an epitaxial process 100 used to deposit a silicon-containing layer. Process 100 includes mounting 110 a patterned substrate into a process chamber and adjusting the internal conditions of the process chamber to a desired temperature and pressure. Step 120 provides a deposition process that forms an epitaxial layer on a monocrystalline surface of a substrate while forming a polycrystalline layer on an amorphous and / or polycrystalline surface of the substrate. During step 130, the deposition process is terminated. Step 140 provides an etching process for etching the substrate surface. Preferably, the polycrystalline layer is also etched at a faster rate than the epitaxial layer. The etching step minimizes or completely removes the polycrystalline layer while removing only the edge portion of the epitaxial layer. During step 150, the etching process is terminated. The thickness of the epitaxial layer and the polycrystalline layer, if any, are determined during step 160. Once the predetermined thickness of the epitaxial layer or polycrystalline layer is achieved, epitaxial process 100 ends at step 170. However, if the predetermined thickness has not been reached, steps 120-160 are repeated in cycles until the predetermined thickness is achieved.

The patterned substrate is mounted to the process chamber during step 110. The patterned substrate is a substrate that includes electrical features formed in or on the substrate surface. The patterned substrate typically includes a monocrystalline surface and at least one second surface that is non-monocrystalline, such as polycrystalline or amorphous surfaces. The monocrystalline surface comprises a bare crystalline substrate or a deposited single crystal layer, typically made of a material such as silicon, silicon germanium or silicon carbon. The polycrystalline or amorphous surface, like the amorphous silicon surface, may comprise an oxide or nitride, in particular a dielectric material such as silicon oxide or silicon nitride.

The epitaxial process 100 begins by adjusting the process chamber containing the patterned substrate during step 110 to a predetermined temperature and pressure. The temperature is adjusted depending on the process performed specifically. In general, the process chamber is maintained at a constant temperature during the epitaxial process 100. However, some steps may be performed at variable temperatures. The process chamber is maintained at a temperature in the range of about 250 ° C to about 1000 ° C, preferably about 500 ° C to about 800 ° C, even more preferably about 550 ° C to about 750 ° C. Suitable temperatures for performing the epitaxial process 100 may depend on the particular precursor used to deposit and / or etch the silicon-containing material during steps 120-140. In one embodiment, it has been found that chlorine (Cl ₂ ) gas works particularly well as an etchant for silicon-containing materials at lower temperatures than processes using more common etchant. Thus, in one embodiment, a suitable temperature for preheating the process chamber is about 750 ° C. or less, preferably about 650 ° C. or less, even more preferably about 550 ° C. or less. The process chamber is typically maintained at a pressure of about 0.1 torr to about 200 torr, preferably about 1 torr to about 50 torr. Pressure may vary during and between process steps 110-160, but generally remains constant.

The deposition process is performed during step 120. The patterned substrate is exposed to a deposition gas to form a nodular layer on the secondary surface while forming an epitaxial layer on the monocrystalline surface. The substrate is exposed to the deposition gas for a period of time from about 0.5 seconds to about 30 seconds, preferably from about 1 second to about 20 seconds, even more preferably from about 5 seconds to about 10 seconds. The specific exposure time of the deposition process is determined in relation to the exposure time during the etching process in step 140 and the specific precursor and temperature used in the process. In general, the substrate is exposed to the deposition gas for a long time to form the epitaxial layer of maximum thickness while forming a polycrystalline layer of minimum thickness that can be easily etched during sequential step 140.

The deposition gas includes at least a silicon source and a carrier gas, and may include at least one second element source, such as a gallium source and / or a carbon source. In addition, the deposition gas may further comprise a dopant compound for providing a source of dopant, such as boron, arsenic, phosphorus, gallium and / or aluminum. In optional embodiments, the deposition gas may include at least one etchant, such as hydrogen chloride or chlorine.

The silicon source is typically provided to the process chamber at a flow rate in the range of about 5 sccm to about 500 sccm, preferably about 10 sccm to about 300 sccm, even more preferably about 50 sccm to about 200 sccm, for example about 100 sccm. Useful silicon sources for deposition gases for depositing silicon-containing compounds include silanes, halogenated silanes and organosilanes. Silanes may be of the higher grade having an _experimental formula Si _x H _{(2x + 2)} , such as silane (SiH ₄ ) and disilane (Si ₂ H ₆ ), trisilane (Si ₃ H ₈ ), tetrasilane (Si ₄ H ₁₀ ), and the like. higher) silanes, and the like. Halogenated silanes hexachlorodisilane (Si ₂ Cl _6), tetrachlorosilane (SiCl _4), dichlorosilane (Cl ₂ SiH _2), and as silane (Cl ₃ SiH) trichlorosilane, the empirical formula X _'y Si _x H _{( 2x + 2-y)} , wherein X '= F, Cl, Br or I. Organosilanes include methylsilane ((CH ₃ ) SiH ₃ ), dimethylsilane ((CH ₃ ) ₂ SiH ₂ ), ethylsilane ((CH ₃ CH ₂ ) SiH ₃ ), methyldisilane ((CH ₃ ) Si ₂ H ₅ ), dimethyldisilane (CH ₃ ) ₂ Si ₂ H ₄ ) and hexamethyldisilane ((CH ₃ ) ₆ Si _{2 )} , the compound having the empirical formula R _y Si _x H _{(2x + 2-y)} Wherein R = methyl, ethyl, propyl or butyl. Organosilane compounds have been found to be preferred silicon sources and carbon sources in embodiments in which carbon is incorporated into the deposited silicon-containing compound. Preferred silicon sources include silanes, dichlorosilanes and disilanes.

Typically, a silicon source along with the carrier gas is provided to the process chamber. The carrier gas has a flow rate of about 1 slm (standard liters per minute) to about 100 slm, preferably about 5 slm to about 75 slm, even more preferably about 10 slm to about 50 slm, for example about 25 slm. The carrier gas may include nitrogen (N ₂ ), hydrogen (H ₂ ), argon, helium and combinations thereof. Inert carrier gases are preferred and include nitrogen, argon, helium and combinations thereof. The carrier gas may be selected based on the precursor (s) used and / or the process temperature during the epitaxial process 100. Typically the carrier gas is the same for each step 110-150. However, some embodiments may use different carrier gases at certain stages. For example, nitrogen may be used as the carrier gas with the silicon source in step 120 and with the etchant in step 140.

Preferably, nitrogen is used as the carrier gas in an embodiment featuring a low temperature (eg, <800 ° C.) process. The low temperature process may be accomplished by using chlorine gas in part in the etching process further disclosed in step 140. Nitrogen remains inert during the low temperature deposition process. Thus nitrogen is not incorporated into the silicon-containing material deposited during the low temperature process. Also, the nitrogen carrier gas does not form a hydrogen-terminated surface like the hydrogen carrier gas. The hydrogen-terminated surface formed by the absorption of hydrogen carrier gas on the substrate surface interferes with the growth rate of the silicon-containing layer. Finally, low temperature processes can take the economic advantage of nitrogen as a carrier gas, since nitrogen is considerably cheaper than hydrogen, argon or helium.

The deposition gas used during step 120 may include at least one second element source, such as a germanium source and / or a carbon source. To form a silicon-containing compound, such as a silicon germanium material, a germanium source may be added to the process chamber along with the silicon source and the carrier gas. Typically the germanium source is provided to the process chamber at a flow rate in the range of about 0.1 sccm to about 20 sccm, preferably about 0.5 sccm to about 10 sccm, even more preferably about 1 sccm to about 5 sccm, for example about 2 sccm. Germanium sources useful for depositing silicon-containing compounds include Germane (GeH ₄ ), higher germanes, and organic germanes only. Higher Germanes include compounds having the empirical Ge _x H _{(2x + 2)} , such as digerman (Ge ₂ H ₆ ), trigerman (Ge ₃ H ₈ ), tetragerman (Ge ₄ H ₁₀ ), and the like. OrganoGermans are methylgerman ((CH ₃ ) GeH ₃ ), dimethylgerman ((CH ₃ ) ₂ GeH ₂ ), ethylgerman ((CH ₃ CH ₂ ) GeH ₃ ), methyldigerman ((CH ₃ ) Ge ₂ H ₅ ), dimethyldigerman ((CH ₃ ) ₂ Ge ₂ H ₄ ) and hexamethyldigerman ((CH ₃ ) ₆ Ge ₂ ). It has been found that Germanic and organic Germanic compounds are preferred germanium and carbon sources in embodiments in which germanium and carbon are incorporated into deposited silicon-containing compounds, ie, SiGe and SiGeC compounds. The germanium concentration in the epitaxial layer ranges from about 1 at% to about 30 at%, for example about 20 at%. The germanium concentration may be differential in the epitaxial layer, and is preferably differentiated so that the germanium concentration is higher in the lower portion of the epitaxial layer than in the upper portion of the epitaxial layer.

Alternatively, a carbon source may be added to the process chamber along with the silicon source and the carrier gas during step 120 to form a silicon-containing compound, such as a silicon carbon material. Typically the carbon source is provided to the process chamber at a flow rate in the range of about 0.1 sccm to about 20 sccm, preferably about 0.5 sccm to about 10 sccm, even more preferably about 1 sccm to about 5 sccm, for example about 2 sccm. Carbon sources useful for depositing silicon-containing compounds include organosilanes, alkyls, alkenes and alkynes of ethyl, propyl and butyl. Such carbon sources include methylsilane (CH ₃ SiH ₃ ), dimethylsilane ((CH ₃ ) ₂ SiH ₂ ), ethylsilane (CH ₃ CH ₂ SiH ₃ ), methane (CH ₄ ), ethylene (C ₂ H ₄ ), Ethyne (C ₂ H ₂ ), propane (C ₃ H ₈ ), propene (C ₃ H ₆ ), butyne (C ₄ H ₆ ), and the like. The carbon concentration of the epitaxial layer is in the range of about 200 ppm to about 5 at%, preferably about 1 at% to about 3 at%, for example about 1.5 at%. In one embodiment, the carbon concentration may be differentiated in the epitaxial layer, preferably to have a lower carbon concentration in the initial portion of the epitaxial layer than in the final portion of the epitaxial layer. Alternatively, both germanium and carbon sources may be added along with the silicon source and the carrier gas during step 120 to form a silicon-containing compound, such as a silicon germanium carbon material.

The deposition gas used during step 120 may further include at least one dopant compound to provide a source of the element dopant, such as boron, arsenic, phosphorus, gallium, or aluminum. Dopants provide silicon-containing compounds deposited with a variety of conductive properties, such as directional electron flow in the required path and control required by the electronic device. Films of silicon-containing compounds are doped with specific dopants to achieve the desired conductive properties. In one embodiment, the silicon-containing compound is doped p-type by using diborane to add boron at a concentration ranging from about 10 ¹⁵ atoms / cm ³ to about 10 ²¹ atoms / cm ³ . In one embodiment, the p-type dopant has a concentration of at least 5 × 10 ¹⁹ atoms / cm ³ . In another example, the p-type dopant ranges from about 1 × 10 ²⁰ atoms / cm ³ to about 2.5 × 10 ²¹ atoms / cm ³ . In another example, the silicon-containing compound is n-type doped with something like phosphorus and / or arsenic in a concentration ranging from about 10 ¹⁵ atoms / cm ³ to 10 ²¹ atoms / cm ³ .

Typically the dopant source is in the process chamber during step 120 at a flow rate in the range of about 0.1 sccm to about 20 sccm, preferably about 0.5 sccm to about 10 sccm, even more preferably about 1 sccm to about 5 sccm, for example about 2 sccm. Is provided. Boron-containing dopants useful as dopant sources include boranes and organoboranes. Boranes include borane, diborane (B ₂ H ₆ ), triborane, tetraborane and pentaborane, alkylboranes comprising compounds having the formula R _x BH _(3-x) , wherein R = methyl, ethyl , Propyl or butyl and x = 1, 2 or 3. Alkylboranes include trimethylborane ((CH ₃ ) ₃ B), dimethylborane ((CH ₃ ) ₂ BH), triethylborane ((CH ₃ CH ₂ ) ₃ B) and diethylborane ((CH ₃ CH ₂ ) ₂ BH). Dopants include alkylphosphines having arsenic (AsH ₃ ), phosphine (PH ₃ ) and empirical R _x PH _(3-x) , where R = methyl, ethyl, propyl or butyl and x = 1, 2 or 3 Alkylphosphines include trimethylphosphine ((CH ₃ ) ₃ P), dimethylphosphine ((CH ₃ ) ₂ PH), triethylphosphine ((CH ₃ CH ₂ ) ₃ P) and diethylphosphine ((CH ₃ CH ₂ ) ₂ PH). Aluminum and gallium dopant sources include alkylated and / or halogenated derivatives initiated by empirical R _x MX _(3-x) , where M = Al or Ga, R = methyl, ethyl, propyl or butyl, X = Cl Or F and x = 0, 1, 2 or 3. Examples of aluminum and gallium dopant sources include trimethylaluminum (Me ₃ Al), triethylaluminum (Et ₃ Al), dimethylaluminum chloride (Me ₂ AlCl), aluminum chloride (AlCl ₃ ), trimethylgallium (Me ₃ Ga), tri Ethyl gallium (Et ₃ Ga), dimethylgallium chloride (Me ₂ GaCl) and gallium chloride (GaCl ₃ ).

During step 130, the deposition process is terminated. In one example, the process chamber may be cleaned with purge gas or carrier gas and / or may be evacuated with a vacuum pump. The purge and / or exhaust process removes excess deposition gas, reaction byproducts and other contaminants. In another example, once the deposition process is terminated, the etching process is initiated immediately at step 140 without purging and / or evacuating the process chamber.

The etching process at step 140 removes the silicon-containing material deposited from the substrate surface during step 120. The etching process removes both epitaxial or monocrystalline materials and amorphous or polycrystalline materials. The polycrystalline layer deposited on the substrate surface, if any, is removed at a faster rate than the epitaxial layer. The time period of the etching process is balanced with the time period of the deposition process resulting in net deposition of the epitaxial layer selectively formed on the desired area of the substrate. Thus, as a final result of the deposition process in step 120 and the etching process in step 140, if any, an epitaxially grown silicon-containing material is formed, while minimizing growth of the polycrystalline silicon-containing material. do.

During step 140, the substrate is exposed to the etching gas for a period of time ranging from about 10 seconds to about 90 seconds, preferably from about 20 seconds to about 60 seconds, even more preferably from about 30 seconds to about 45 seconds. . The etching gas includes at least one etchant and a carrier gas. Typically the etchant is provided to the process chamber at a flow rate in the range of about 10 sccm to about 700 sccm, preferably about 50 sccm to about 500 sccm, even more preferably about 100 sccm to about 400 sccm, for example about 200 sccm. The etchant used in the etching gas may include chlorine (Cl ₂ ), hydrogen chloride (HCl), boron trichloride (BCl ₃ ), carbon tetrachloride (CCl ₄ ), chlorine trifluoride (ClF ₃ ), and combinations thereof. Preferably chlorine or hydrogen chloride is used as the etchant.

Typically the etchant is provided to the process chamber along with the carrier gas. The carrier gas has a flow rate in the range of about 1 slm to about 100 slm, preferably about 5 slm to about 75 slm, even more preferably about 10 slm to about 50 slm, for example about 25 slm. Carrier gases include nitrogen (N ₂ ), hydrogen (H ₂ ), argon, helium and combinations thereof. In some embodiments, an inert carrier gas is preferred and the inert carrier gas includes nitrogen, argon, helium, and combinations thereof. The carrier gas may be selected based on the specific precursor (s) and / or temperature used during the epitaxial process 100. Typically the same carrier gas is used throughout each of the steps 110-150. However, some embodiments may use a different carrier gas than that used in the deposition process during the etching process. In one embodiment, the preferred etchant is chlorine gas, especially when the AGS process is performed at low temperatures (eg, <800 ° C.). For example, the etching gas includes chlorine as an etchant and nitrogen as a carrier gas and is exposed to the substrate surface at a temperature in the range of about 500 ° C to about 750 ° C. In another example, the etching gas containing chlorine and nitrogen is exposed to the substrate surface at a temperature in the range of about 250 ° C to about 500 ° C.

The etching process is terminated during step 150. In one embodiment, the process chamber may be purged with purge gas or carrier gas and / or evacuated with a vacuum pump. Purification and / or exhaust processes remove excess etching gas, reaction byproducts and other contaminants. In another example, once the etching process is terminated, step 160 begins immediately without purging and / or evacuating the process chamber.

The thickness of the epitaxial layer and the polycrystalline layer can be determined during step 160. Once the predetermined thickness is achieved, epitaxial process 100 ends at step 170. However, if the predetermined thickness has not been achieved, steps 120-160 are repeated in cycles until the desired thickness is achieved. Typically the epitaxial layer is grown to have a thickness in the range from about 10 kPa to about 2,000 kPa, preferably from about 100 kPa to about 1,500 kPa, even more preferably from about 400 kPa to about 1,200 kPa. Typically the polycrystalline layer, if any, is deposited to a thickness in the range of atomic layers to about 500 GPa. The desired or predetermined thickness of the epitaxial silicon-containing layer or polycrystalline silicon-containing layer depends on the particular manufacturing process. In one example, the epitaxial layer can reach a predetermined thickness while the polycrystalline layer is too thick. The excess polycrystalline layer can be further etched by repeating steps 140-160 while skipping steps 120 and 130.

As shown in Figures 2A-2E, in one embodiment, source / drain extensions are formed in the MOSFET device, and silicon containing layers are selectively deposited epitaxially on the substrate surface. 2A shows source / drain region 232 formed by implanting ions into the surface of substrate 230. Segments of source / drain region 232 are bridged by gate oxide layer 235 and gate 236 formed over spacer 234. To form the source / drain extensions, portions of the source / drain regions 232 are etched and wet-cleaned to form recesses 238 as shown in FIG. 2B. Etching of the gate 236 may be prevented by depositing a hardmask prior to etching the portion of the source / drain region 232.

2C illustrates one embodiment of the epitaxial process disclosed herein, wherein the silicon-containing epitaxial layer 240 and the optional polycrystalline layer 242 are selectively deposited simultaneously without being deposited on the spacer 234. do. Polycrystalline layer 242 is selectively formed on gate 236 by adjusting the deposition and etching process in steps 120 and 140 of epitaxial process 100. Alternatively, polycrystalline layer 242 is etched continuously from gate 236 as epitaxial layer 240 is deposited on source / drain regions 232.

In another example, silicon-containing epitaxial layer 240 and polycrystalline layer 242 are SiGe-containing layers having a germanium concentration in the range of about 1 at% to about 50 at%, preferably up to about 24 at%. Multiple SiGe-containing layers comprising varying amounts of silicon and germanium are stacked to form a silicon-containing epitaxial layer 240 having differential element concentrations. For example, the first SiGe-layer may be deposited at a germanium concentration in the range of about 15 at% to about 25 at% and the second SiGe- layer may be deposited at a germanium concentration in the range of about 25 at% to about 35 at%.

In another example, silicon-containing epitaxial layer 240 and polycrystalline layer 242 may be from about 200 ppm to about 5 at%, preferably up to about 3 at%, even more preferably from about 1 at% to about 2 at%, eg For example, a SiC-containing layer having a carbon concentration in the range of about 1.5 at%. In another embodiment, the silicon-containing epitaxial layer 240 and the polycrystalline layer 242 have a germanium concentration in the range of about 1 at% to about 50 at%, preferably up to about 24 at%, and about 200 ppm to about 5 at%, preferably Preferably a SiGeC-containing layer having a carbon concentration in the range of about 3 at% or less, more preferably about 1 at% to about 2 at%, for example about 1.5 at%.

Multiple layers comprising Si, SiGe, SiC or SiGeC may be deposited out of order to form differential element concentrations within the silicon-containing epitaxial layer 240. Generally the silicon-containing layers dopants having a concentration in the range of about 1 × 10 ¹⁹ atoms / cm 3 to about 2.5 × 10 ²¹ atoms / cm 3, preferably about 5 × 10 ¹⁹ atoms / cm 3 to about 2 × 10 ²⁰ atoms / cm 3 (Eg, boron, arsenic, phosphorus, gallium or aluminum). Dopants added to the individual layers of silicon-containing material are differential dopants. For example, silicon-containing epitaxial layer 240 may comprise a first SiGe-containing layer having a dopant concentration (eg, boron) in the range of about 5 × 10 ¹⁹ atoms / cm 3 to about 1 × 10 ²⁰ atoms / cm 3. It is formed by depositing a second SiGe-containing layer having a dopant concentration (eg, boron) in the range of 1 × 10 ²⁰ atoms / cm 3 to about 2 × 10 ²⁰ atoms / cm 3.

During the next step, FIG. 2D shows a nitride spacer (eg, Si ₃ N ₄ ) deposited on spacer 244, generally spacer 234. Spacers 244 are typically deposited in different chambers by CVD or ALD techniques. Thus, the substrate is removed from the process chamber used to deposit the silicon-containing epitaxial layer 240. During the transfer between the two chambers, the substrate may be exposed to atmospheric conditions, such as temperature, pressure or atmospheric air containing water and oxygen. As the spacer 244 is deposited, or as another semiconductor process (eg, annealing, deposition, or ion implantation) is performed, the substrate is subjected to a second time prior to depositing the elevated layer 248. May be exposed to atmospheric conditions. In one embodiment, an epitaxial layer (not shown) having no germanium or having minimal germanium (eg, less than about 5 at%) is deposited over epitaxial layer 240 before the substrate is exposed to atmospheric conditions. This is because the native oxide is more easily removed from the epitaxial layer containing the minimum germanium concentration than from the epitaxial layer formed at the germanium concentration of greater than about 5 at%.

FIG. 2E shows another example where the ridge layer 248 comprising the silicon-containing material is an epitaxially deposited epitaxial layer 240 (eg, doped SiGe). During the deposition process, polycrystalline layer 242 is further grown, deposited or etched on gate 236.

In a preferred embodiment, the raised layer 248 is epitaxially deposited silicon with or without trace amounts of germanium or carbon. However, in alternative embodiments, raised layer 248 contains germanium and / or carbon. For example, the raised layer 248 may have about 5 at% or less germanium. In another example, raised layer 248 may have about 2 at% or less of carbon. The raised layer 248 may also be doped with a dopant, such as boron, arsenic, phosphorus, aluminum or gallium.

Silicon-containing compounds include bipolar device fabrication (eg, base, emitter, collector, emitter contact), BiCMOS device fabrication (eg, base, emitter, collector, emitter contact) and CMOS device fabrication (eg For example, to deposit silicon-containing layers used for channels, sources / drains, source / drain extensions, raised sources / drains, substrates, modified silicon, silicon on insulators and contact plugs). Used in embodiments of the process. Still other embodiments of the process show the growth of silicon-containing layers that can be used for gates, base contacts, collector contacts, emitter contacts, raised sources / drains, and other applications.

The processes are very useful for depositing selective, epitaxial silicon-containing layers on MOSFETs and bipolar transistors as shown in FIGS. 3A-3C. 3A-3B show epitaxially grown silicon-containing compounds on MOSFET devices. Silicon-containing compounds are deposited on the source / drain features of the device. The silicon-containing compound grows in contact with the crystal lattice of the underlying layer and maintains this arrangement until the silicon-containing compound is grown to the desired thickness. 3A shows a silicon-containing compound deposited into a recessed source / drain layer, and FIG. 3B shows a silicon-containing compound deposited into a recessed source / drain layer and a raised source / drain layer.

Source / drain regions 312 are formed by ion implantation. In general, substrate 310 is doped n-type, while source / drain region 312 is doped p-type. Silicon-containing epitaxial layer 313 is selectively grown on source / drain regions 312 and / or directly on substrate 310. Silicon-containing epitaxial layer 314 is selectively grown on silicon-containing layer 313 in accordance with aspects of the specification. Gate oxide layer 318 entangles segmented silicon-containing layer 313. In general, gate oxide layer 318 is comprised of silicon dioxide, silicon oxynitride or hafnium oxide. Spacer 316 partially surrounds gate oxide layer 318, and spacer 316 is typically a separation material, such as a nitride / oxide stack (eg, Si ₃ N ₄ / SiO ₂ / Si ₃ N ₄ ). to be. Gate layer 322 (eg, polysilicon) may include a protective layer 319, such as silicon dioxide, along a vertical side, as shown in FIG. 3A. Alternatively, gate layer 322 may include an off-set layer 320 (eg, Si ₃ N ₄ ) and spacer 316 deposited on one side.

In another embodiment, FIG. 3C shows a silicon-containing epitaxial layer 334 deposited as a base layer of a bipolar transistor. Silicon-containing epitaxial layer 334 is selectively grown in accordance with various embodiments of the present invention. Silicon-containing epitaxial layer 334 is deposited on n-type collector layer 332 previously deposited on substrate 330. In addition, the transistor may include a separation layer 333 (eg, SiO ₂ or Si ₃ N ₄ ), a contact layer 336 (eg, heavily doped poly-Si), an off-set layer 338 (eg, For example, Si ₃ N ₄ ), and a second separation layer 340 (eg, SiO ₂ or Si ₃ N ₄ ) are further included.

In an alternative embodiment, FIG. 4 shows an epitaxial process 400 that can be used to selectively deposit a silicon-containing material / layer. Epitaxial process 400 includes at least two deposition processes followed by an etching process. The first deposition process includes a deposition gas containing a silicon source while the second deposition process contains a second element source, such as germanium, carbon or dopant (eg, boron, arsenic, phosphorus, gallium or aluminum). It includes a vapor deposition gas. Process parameters similar to those used in epitaxial process 100 are used in epitaxial process 400, such as temperature, pressure, flow rate, carrier gas, and precursors.

The epitaxial process 400 includes a step 410 of mounting a patterned substrate in the process chamber and adjusting the process chamber to a predetermined temperature. Step 420 provides a first deposition process for forming an epitaxial layer on a monocrystalline surface while forming a polycrystalline layer on a secondary surface, such as an amorphous and / or polycrystalline surface. The epitaxial layer and the monocrystalline layer are formed from a deposition gas containing a silicon source. During step 430, the first deposition process is terminated. Step 440 provides a second deposition process for sustaining epitaxial layer growth on the monocrystalline surface and continuing polycrystalline layer formation on the second surface. The epitaxial layer and polycrystalline layer are further grown by exposing the substrate surface to a deposition gas comprising a second element source. In step 450, the second deposition process is terminated. Step 460 provides an etching process for etching the exposed silicon-containing layers. The etching process completely removes or minimizes the polycrystalline layer while removing only the edge portion of the epitaxial layer, depending on the rate at which each material is removed. During step 470, the etching process is terminated. The thickness of the epitaxial layer and the polycrystalline layer, if any, is determined during step 480. If the predetermined thickness is achieved, epitaxial process 400 ends at step 490. However, if either layer has not reached the predetermined thickness, steps 420-480 are repeated as cycles until the predetermined thickness is achieved.

The epitaxial process 400 begins with step 410 by adjusting the process chamber containing the patterned substrate to a predetermined temperature. Temperature and pressure are adjusted depending on the specific process performed. In general, the process chamber is maintained at a constant temperature during the epitaxial process 400. However, some steps may be performed at varying temperatures. The process chamber is maintained at a temperature in the range of about 250 ° C to about 1000 ° C, preferably about 500 ° C to about 800 ° C, even more preferably about 550 ° C to about 750 ° C. The temperature suitable for performing epitaxial process 400 may depend on the particular precursor used to deposit and / or etch the silicon-containing material during steps 420-480. In one embodiment, it has been found that chlorine (Cl ₂ ) gas works particularly well for silicon-containing materials at lower temperatures in processes using other more common etchant. Thus, in one embodiment, a suitable temperature for preheating the process chamber is about 750 ° C. or less, preferably about 650 ° C. or less, even more preferably about 550 ° C. or less. Typically the process chamber is maintained at a pressure between about 0.1 Torr and about 200 Torr, preferably between about 1 Torr and about 50 Torr. Pressure may vary during and between process steps 410-480, but generally remains constant.

The first deposition process is performed during step 420. The patterned substrate is exposed to the first deposition gas to form an epitaxial layer on the monocrystalline surface while forming the polycrystalline layer on the secondary surface. The substrate is exposed to the first deposition gas for a period of time from about 0.5 seconds to about 30 seconds, preferably from about 1 second to about 20 seconds, even more preferably from about 5 seconds to about 10 seconds. The specific exposure time of the deposition process is determined in relation to the exposure time during the etching process in step 460 and the specific precursor and temperature used in the process. In general, the substrate is exposed to the first deposition gas for a long time to form a minimized thickness of the epitaxial layer while forming a minimized thickness of the polycrystalline layer that can be easily etched during sequential step 460.

The first deposition gas includes at least a silicon source and a carrier gas. The first deposition gas may also include a second element source and / or a dopant compound, but preferably the second element source and the dopant compound are included in the second deposition gas. Thus, in one aspect, the first deposition gas may comprise a silicon source, a second element source and a dopant source. In another aspect, the first deposition gas includes a silicon source and a second element source. In another aspect, the first deposition gas includes a silicon source and a dopant source. In alternative embodiments, the first deposition gas may include at least one etchant, such as hydrogen chloride or chlorine.

Typically the silicon source is provided to the process chamber at a flow rate in the range of about 5 sccm to about 500 scmm, preferably about 10 sccm to about 300 sccm, even more preferably about 50 sccm to about 200 sccm, for example about 100 sccm. Preferred silicon sources include silanes, dichlorosilanes and disilanes.

Typically the silicon source is provided to the process chamber along with the carrier gas. The carrier gas has a flow rate of about 1 slm to about 100 slm, preferably about 5 slm to about 75 slm, even more preferably about 10 slm to about 50 slm, for example about 25 slm. The carrier gas may include nitrogen (N ₂ ), hydrogen (H ₂ ), argon, helium and combinations thereof. In some embodiments, an inert carrier gas is preferred and the inert carrier gas includes nitrogen, argon, helium, and combinations thereof. Preferably, the carrier gas used during the entire epitaxial process 400 is nitrogen, for the reasons disclosed above.

During step 430, the first deposition process is terminated. In one example, the process chamber may be purged with purge gas and / or carrier gas and / or evacuated with a vacuum pump. Purification and / or exhaust processes remove excess deposition gas, reaction byproducts and other contaminants. In another example, once the first deposition process is terminated, the second deposition process begins at step 440 immediately without purging and / or evacuating the process chamber.

The deposition gas used during step 440 includes a carrier gas and at least one second element source, such as a germanium source, a carbon source and / or a dopant compound. Alternatively, the silicon source can be included in the second deposition gas. The second element source is added to the process chamber along with the carrier gas to sustain the growth of the silicon-containing compound deposited during step 420. The silicon-containing compound may have various compounds controlled by a particular second element source and the concentration of the second element source. Typically, the second element source is provided to the chamber in a process at a flow rate in the range of about 0.1 sccm to about 20 sccm, preferably about 0.5 sccm to about 10 sccm, even more preferably about 1 sccm to about 5 sccm, for example about 2 sccm. . The germanium source, carbon source and dopant compound are selected from the precursors disclosed above.

During step 450, the second deposition process is terminated. In one example, the process chamber may be cleaned with a purge gas or carrier gas and / or evacuated with a vacuum pump. Purification and / or exhaust processes remove excess deposition gas, reaction byproducts and other contaminants. In another example, once the second deposition process is terminated, the etching process begins immediately at step 460 without purging and / or evacuating the process chamber.

In step 460 the etching process removes material deposited during steps 420-440 from the substrate surface. The etching process removes both epitaxial or monocrystalline materials and amorphous and / or polycrystalline materials. Polycrystalline layers deposited on the substrate surface, if any, are removed at a faster rate than epitaxial layers. The time period of the etching process is balanced with the time period of the two deposition processes. Thus, the final result of the deposition process in steps 420-44 and the etching process in step 460, if any, is optionally epitaxially grown silicon-containing material while minimizing growth of the polycrystalline silicon-containing material. To form.

During step 460, the substrate is exposed to the etching gas for a time period in a range from about 10 seconds to about 90 seconds, preferably from about 20 seconds to about 60 seconds, even more preferably from about 30 seconds to about 45 seconds. The etching gas includes at least one etchant and a carrier gas. Typically the etchant is provided to the process chamber at a flow rate in the range of about 10 sccm to about 700 sccm, preferably about 50 sccm to about 500 sccm, even more preferably about 100 sccm to about 400 sccm, for example about 200 sccm. The etchant used in the etching gas may include chlorine (Cl ₂ ), hydrogen chloride (HCl), boron trichloride (BCl ₃ ), carbon tetrachloride (CCl ₄ ), chlorine trifluoride (ClF ₃ ) and combinations thereof. Preferably chlorine or hydrogen chloride is used as the etchant.

Typically the etchant is provided to the process chamber along with the carrier gas. The carrier gas has a flow rate in the range of about 1 slm to about 100 slm, preferably about 5 slm to about 75 slm, even more preferably about 10 slm to about 50 slm, for example about 25 slm. The carrier gas may include nitrogen (N ₂ ), hydrogen (H ₂ ), argon, helium and combinations thereof. In some embodiments, an inert carrier gas is preferred and the inert carrier gas includes nitrogen, argon, helium, and combinations thereof. The carrier gas may be selected depending on the specific precursor (s) and / or temperature used during the epitaxial process 400. Typically the same carrier gas is used for each step 420-480. However, some embodiments may use a different carrier gas than that used in the deposition process during the etching process. In one embodiment, the preferred etchant is chlorine gas, especially when the AGS process is performed at low temperatures (eg, <800 ° C.). For example, the etching gas includes chlorine as an etchant and nitrogen as a carrier gas and is exposed to the substrate surface at a temperature in the range of about 500 ° C to about 750 ° C.

The etching process ends during step 470. In one example, the process chamber may be cleaned with a purge gas or carrier gas and / or evacuated with a vacuum pump. The purge and / or exhaust process removes excess etching gas, reaction byproducts and other contaminants. In another example, once the etching process is terminated, step 480 begins immediately without purging and / or evacuating the process chamber.

The thickness of the epitaxial layer and the polycrystalline layer may be determined during step 480. Once the predetermined thickness is achieved, epitaxial process 400 ends at step 490. However, if the predetermined thickness has not been achieved, steps 420-480 are repeated with cycles until the desired thickness is achieved. Typically the epitaxial layer is grown to have a thickness in the range from about 10 kPa to about 2,000 kPa, preferably from about 100 kPa to about 1,500 kPa, even more preferably from about 400 kPa to about 1,200 kPa. Typically the polycrystalline layer, if any, is deposited to a thickness in the range of atomic layers to about 500 GPa. The desired or predetermined thickness of the epitaxial silicon-containing layer or polycrystalline silicon-containing layer depends on the particular manufacturing process. In one example, the epitaxial layer can reach a predetermined thickness while the polycrystalline layer is too thick. The excess polycrystalline layer can be further etched by repeating steps 420-480 while omitting steps 460 and 470. Likewise, in other embodiments, steps 420, 440, and 460 may be omitted separately while performing epitaxial process 400. By skipping steps 420, 440, 460, the element concentration and thickness of the deposited silicon-containing material can be controlled.

Embodiments of the present invention disclose a process for depositing silicon-containing compounds on various substrates. Substrates that can be used in embodiments of the present invention include crystalline silicon (eg, Si <100> and Si <111>), silicon oxide, silicon germanium, doped or undoped wafers, and wafers that are not patterned or patterned. Including but not limited to the same semiconductor wafer. Substrates can have a variety of geometries (eg, round, square and rectangular) and sizes (eg, 200 mm OD, 300 mm OD).

In one embodiment, the silicon-containing compound deposited by the process disclosed herein comprises a germanium concentration in the range of about 0 at% to about 95 at%. In another embodiment, the germanium concentration is in the range of about 1 at% to about 30 at%, preferably about 15 at% to about 30 at%, for example about 20 at%. The silicon-containing compound also includes a carbon concentration in the range of about 0 at% to about 5 at%. In another aspect, the carbon concentration is in the range of about 200 ppm to about 3 at%, preferably about 1.5 at%.

Silicon-containing compound films of germanium and / or carbon are formed by the various processes of the present invention and may have a constant, sporadic or differential element concentration. Differential silicon germanium films are disclosed in US Patent Application No. 10 / 014,466, published as US Pat. No. 6,770,134 and US Patent Publication No. 20020174827, all of which are assigned to Applied Materials, Inc. Reference is made herein to disclose a method of deposition. In one embodiment, a silicon source (eg, SiH ₄ ) and germanium source (eg, GeH ₄ ) are used to selectively epitaxially deposit silicon germanium containing films. In this example, the ratio of silicon source and germanium source can be varied to control element concentrations such as silicon and germanium while the differential films are growing. In another example, a silicon source and a carbon source (eg, CH ₃ SiH ₃ ) are used to selectively epitaxially deposit silicon carbon-containing films. The ratio of silicon source to carbon source can be varied to control element concentration while growing homogeneous or differential films. In another example, a silicon source, germanium source, and carbon source are used to selectively epitaxially deposit silicon germanium carbon-containing films. The proportions of silicon, germanium and carbon sources are modified independently for control of element concentration while growing homogeneous or differential films.

MOSFET devices formed by the processes disclosed herein may include PMOS components or NMOS components. PMOS components with p-type channels have holes responsible for channel conduction, while NMOS components with n-type channels have electrons responsible for channel conduction. Thus, for example, a silicon-containing material such as SiGe may be deposited in the recessed region to form the PMOS component. In another example, a silicon-containing film, such as SiC, may be deposited in the recessed region to form an NMOS component. SiGe is used in the PMOS field for several reasons. SiGe materials can be more integrated with boron than silicon alone to lower junction resistivity. In addition, the SiGe / silicide layer interface at the substrate surface has a lower Schottky barrier than the Si / silicide interface.

In addition, SiGe epitaxially grown on silicon has a compressive stress inside the film, because the lattice constant of SiGe is larger than that of silicon. The compressive stress is transmitted in lateral dimensions to create compressive stress in the PMOS channel and increase the mobility of the holes. For NMOS applications, SiC can be used in recessed regions to create tensile stress in the channel because the lattice constant of SiC is less than the lattice constant of silicon. Tensile stress is transferred to the channel to increase electron mobility. Thus, in one embodiment, the first silicon-containing layer is formed with a first lattice strain value and the second silicon-containing layer is formed with a second lattice strain value. For example, a SiC layer having a thickness of about 50 GPa to about 200 GPa is deposited on the substrate surface, and a SiGe layer having a thickness of about 150 GPa to about 1000 GPa is sequentially deposited on the SiC layer. The SiC layer is epitaxially grown and has less strain than the SiGe layer epitaxially grown in the SiC layer.

In the embodiments disclosed herein, the silicon-containing compound films are selectively epitaxially deposited by a chemical vapor deposition (CVD) process. Chemical vapor deposition processes include atomic layer deposition (ALD) processes and / or atomic layer epitaxial (ALE) processes. Chemical vapor deposition includes plasma assisted CVD (PA-CVD), atomic layer CVD (ALCVD), organometallic or metalorganic CVD (OMCVD or MOCVD), laser assisted CVD (LA-CVD), ultraviolet CVD (UV-CVD), hot -Use of various techniques such as wire (HWCVD), reduced pressure CVD (RP-CVD), ultra-high vacuum CVD (UHV-CVD), and the like. In one embodiment, the preferred process is to use thermal CVD to epitaxially grow or deposit a silicon-containing compound, wherein the silicon-containing compound comprises silicon, SiGe, SiC, SiGeC, doped variants thereof, and combinations thereof. do.

시스템 및 Poly Gen

시스템을 포함한다. ALD 장치는 'Gas Delivery Apparatus and Methods for ALD"란 명칭으로, 어플라이드 머티리얼스사에 양도된 미국 특허 공개 번호 20030079686호로서 공개된, 2001년 12월 21일자로 출원된 미국 특허 출원 번호 10/032,284호에 개시되며, 상기 문헌은 상기 장치를 설명하기 위해 본 명세서에서 참조된다. 업계에 공지된 다른 장치로는 배치(batch), 고온 퍼니스가 포함된다.The process of the present invention can be carried out in equipment known in ALE, CVD and ALD techniques. The apparatus may include a plurality of gas lines to maintain the deposition gas and the etching gas that are separated before entering the process chamber. The gas then comes into contact with the heated substrate on which the silicon-containing compound films are grown. Hardware that can be used to deposit silicon-containing films is Epi Centura available from Applied Materials, Inc., located in Santa Clara, California.

System and Poly Gen

It includes a system. The ALD device is described in US Patent Application No. 10 / 032,284, filed Dec. 21, 2001, published as US Patent Publication No. 20030079686, assigned to Applied Materials, Inc., entitled "Gas Delivery Apparatus and Methods for ALD." This document is referred to herein to describe the device Other devices known in the art include batches, high temperature furnaces.

Examples

Examples assumed below are performed to form a raised source drain (ESD) structure on a substrate surface. The patterned substrate has a monocrystalline surface having source / drain features and gates formed within the substrate surface and spacers formed therebetween.

Example 1: Selective epitaxy of silicon using Cl ₂ etchant -The substrate was placed in a process chamber maintained heated to 550 ° C. The process chamber was maintained at a pressure of about 15 Torr. The substrate surface was exposed to a flow of deposition gas containing silane with a flow rate of 100 sccm and nitrogen with a flow rate of 25 slm for 7 seconds. The substrate was then exposed to a flow of etch gas containing chlorine gas with a flow rate of 20 sccm and nitrogen with a flow rate of 25 slm for 10 seconds. The deposition gas exposure and etching gas exposure cycles were repeated 50 times to form an epitaxially grown silicon layer on the exposed monocrystalline portion of the substrate. The silicon epitaxial layer had a thickness of about 1000 GPa.

Example 2: Selective epitaxy of silicon germanium using Cl ₂ etchant -The substrate was placed in a process chamber maintained heated to 550 ° C. The process chamber was maintained at a pressure of about 15 Torr. The substrate surface was exposed to a flow of deposition gas comprising silane with a flow rate of 100 sccm, Germanic with a flow rate of 3 sccm and nitrogen with a flow rate of 25 slm for 8 seconds. The substrate was then exposed to a flow of etch gas containing chlorine gas with a flow rate of 20 sccm and nitrogen with a flow rate of 25 slm for 10 seconds. The deposition gas exposure and etch gas exposure cycles were repeated 50 times to form an epitaxially grown silicon-containing layer on the exposed monocrystalline portion of the substrate. The silicon-containing epitaxial layer had a thickness of about 1700 GPa.

Example 3: Selective epitaxy of silicon germanium using Cl ₂ etchant -The substrate was placed in a process chamber maintained heated to 550 ° C. The process chamber was maintained at a pressure of about 15 Torr. The substrate surface was exposed to a flow of deposition gas containing silane with a flow rate of 100 sccm and nitrogen with a flow rate of 25 slm for 7 seconds. The substrate surface was then exposed to a flow of a second deposition gas containing Germanic with a flow rate of 5 sccm and nitrogen with a flow rate of 25 slm for 7 seconds. The substrate was exposed to etching gas containing chlorine gas with a flow rate of 20 sccm and nitrogen with a flow rate of 25 slm for 10 seconds. The deposition gas exposure and etch gas exposure cycles were repeated 50 times to form an epitaxially grown silicon-containing layer on the exposed monocrystalline portion of the substrate. The silicon-containing epitaxial layer had a thickness of about 1800 mm 3.

Example 4: Selective epitaxy of silicon carbon using Cl ₂ etchant -The substrate was placed in a process chamber maintained heated to 550 ° C. The process chamber was maintained at a pressure of about 15 Torr. The substrate surface was exposed to a flow of deposition gas comprising silane with a flow rate of 100 sccm, methylsilane with a flow rate of 1 sccm and nitrogen with a flow rate of 25 slm for 8 seconds. The substrate was exposed to a flow of etch gas containing chlorine gas with a flow rate of 20 sccm and nitrogen with a flow rate of 25 slm for 10 seconds. The deposition gas exposure and etch gas exposure cycles were repeated 50 times to form an epitaxially grown silicon-containing layer on the exposed monocrystalline portion of the substrate. The silicon-containing epitaxial layer had a thickness of about 1600 mm 3.

Example 5 Selective Epitaxy of Silicon Carbon Using Cl ₂ Etchant —The substrate was placed in a process chamber maintained heated to 550 ° C. The process chamber was maintained at a pressure of about 15 Torr. The substrate surface was exposed to a flow of deposition gas containing silane with a flow rate of 100 sccm and nitrogen with a flow rate of 25 slm for 7 seconds. The substrate surface was exposed to a flow of a second deposition gas comprising methylsilane having a flow rate of 5 sccm and nitrogen having a flow rate of 25 slm for 7 seconds. The substrate was exposed to an etching gas containing chlorine gas having a flow rate of 20 sccm and nitrogen having a flow rate of 25 slm for 10 seconds. The deposition gas exposure and etch gas exposure cycles were repeated 50 times to form an epitaxially grown silicon-containing layer on the exposed monocrystalline portion of the substrate. The silicon-containing epitaxial layer had a thickness of about 1800 mm 3.

Example 6 Selective Epitaxy of Silicon Using HCl Etchant -The substrate was placed in a process chamber maintained heated to 700 ° C. The treatment chamber was maintained at a pressure of about 15 Torr. The substrate surface was then exposed to a flow of deposition gas containing silane with a flow rate of 100 sccm and hydrogen with a flow rate of 25 slm for 7 seconds. The substrate was exposed to an etching gas containing hydrogen chloride having a flow rate of 200 sccm and hydrogen having a flow rate of 25 slm for 40 seconds. The deposition gas exposure and etching gas exposure cycles were repeated 10 times to form an epitaxially grown silicon layer on the exposed monocrystalline portion of the substrate. The silicon epitaxial layer had a thickness of about 800 GPa.

Example 7: Selective epitaxy of silicon germanium with HCl etchant —The substrate was placed in a process chamber maintained heated to 700 ° C. The treatment chamber was maintained at a pressure of about 15 Torr. The substrate surface was then exposed to a flow of deposition gas comprising silane with a flow rate of 100 sccm, Germane with a flow rate of 3 sccm, and hydrogen with a flow rate of 25 slm for 8 seconds. The substrate was exposed to an etching gas containing hydrogen chloride having a flow rate of 200 sccm and hydrogen having a flow rate of 25 slm for 40 seconds. The deposition gas exposure and etching gas exposure cycles were repeated 20 times to form an epitaxially grown silicon-containing layer on the exposed monocrystalline portion of the substrate. The silicon-containing epitaxial layer had a thickness of about 1500 mm 3.

Example 8 Selective epitaxy of silicon germanium using HCl etchant —The substrate was placed in a process chamber maintained heated to 700 ° C. The treatment chamber was maintained at a pressure of about 15 Torr. The substrate surface was then exposed to a flow of deposition gas containing silane with a flow rate of 100 sccm and hydrogen with a flow rate of 25 slm for 7 seconds. The substrate was exposed to a flow of a second deposition gas containing Germanic with a flow rate of 5 sccm and hydrogen with a flow rate of 25 slm for 7 seconds. The substrate was exposed to an etching gas containing hydrogen chloride having a flow rate of 200 sccm and hydrogen having a flow rate of 25 slm for 40 seconds. The deposition gas exposure and etching gas exposure cycles were repeated 20 times to form an epitaxially grown silicon-containing layer on the exposed monocrystalline portion of the substrate. The silicon-containing epitaxial layer had a thickness of about 1600 mm 3.

Example 9 Selective Epitaxy of Silicon Carbon Using HCl Etchant -The substrate was placed in a process chamber maintained heated to 700 ° C. The treatment chamber was maintained at a pressure of about 15 Torr. The substrate surface was then exposed to a flow of deposition gas comprising silane with a flow rate of 100 sccm, methylsilane with a flow rate of 1 sccm and hydrogen with a flow rate of 25 slm for 8 seconds. The substrate was exposed to an etching gas containing hydrogen chloride having a flow rate of 200 sccm and hydrogen having a flow rate of 25 slm for 40 seconds. The deposition gas exposure and etching gas exposure cycles were repeated 20 times to form an epitaxially grown silicon-containing layer on the exposed monocrystalline portion of the substrate. The silicon epitaxial layer had a thickness of about 1500 kPa.

Example 10 Selective Epitaxy of Silicon Carbon Using HCl Etchant —The substrate was placed in a process chamber maintained heated to 700 ° C. The treatment chamber was maintained at a pressure of about 15 Torr. The substrate surface was then exposed to a flow of deposition gas containing silane with a flow rate of 100 sccm and hydrogen with a flow rate of 25 slm for 7 seconds. The substrate was exposed to a flow of a second deposition gas containing Germanic with a flow rate of 5 sccm and hydrogen with a flow rate of 25 slm for 7 seconds. The substrate was exposed to an etching gas containing hydrogen chloride having a flow rate of 200 sccm and hydrogen having a flow rate of 25 slm for 40 seconds. The deposition gas exposure and etching gas exposure cycles were repeated 20 times to form an epitaxially grown silicon-containing layer on the exposed monocrystalline portion of the substrate. The silicon-containing epitaxial layer had a thickness of about 1600 mm 3. Exposed dielectric portions of the substrate surface, such as gates, were formed from the deposition gas without limited polycrystalline growth or polycrystalline growth.

Example 11 Selective Epitaxy of Silicon Doped with B and Etched with Cl ₂ —The substrate was placed in a process chamber maintained heated to 550 ° C. FIG. The treatment chamber was maintained at a pressure of about 15 Torr. The substrate surface was then exposed to a flow of deposition gas comprising silane with a flow rate of 100 sccm, diborane with a flow rate of 3 sccm, and nitrogen with a flow rate of 25 slm for 7 seconds. The substrate was exposed to an etching gas containing chlorine gas having a flow rate of 20 sccm and nitrogen having a flow rate of 25 slm for 10 seconds. The deposition gas exposure and etching gas exposure cycles were repeated 50 times to form an epitaxially grown silicon layer on the exposed monocrystalline portion of the substrate. The silicon epitaxial layer had a thickness of about 1000 GPa.

Example 12 Selective Epitaxy of Silicon Germanium Doped with B and Etched with Cl ₂ —The substrate was placed in a process chamber maintained heated to 550 ° C. FIG. The treatment chamber was maintained at a pressure of about 15 Torr. The substrate surface was then exposed to a flow of deposition gas comprising silane with a flow rate of 100 sccm, germane with a flow rate of 3 sccm, diborane with a flow rate of 3 sccm, and nitrogen with a flow rate of 25 slm for 8 seconds. The substrate was exposed to an etching gas containing chlorine gas having a flow rate of 20 sccm and nitrogen having a flow rate of 25 slm for 10 seconds. The deposition gas exposure and etching gas exposure cycles were repeated 50 times to form an epitaxially grown silicon-containing layer on the exposed monocrystalline portion of the substrate. The silicon-containing epitaxial layer had a thickness of about 1700 GPa.

Example 13: Selective epitaxy of silicon germanium doped with B and etched with Cl ₂ -The substrate was placed in a process chamber maintained heated to 550 ° C. The treatment chamber was maintained at a pressure of about 15 Torr. The substrate surface was then exposed to a flow of deposition gas comprising silane with a flow rate of 100 sccm, diborane with a flow rate of 3 sccm and nitrogen with a flow rate of 25 slm for 7 seconds. The substrate surface was exposed to a second deposition gas containing Germanic with a flow rate of 5 sccm and nitrogen with a flow rate of 25 slm for 7 seconds. The substrate was then exposed for 10 seconds to an etching gas comprising chlorine gas having a flow rate of 20 sccm and nitrogen having a flow rate of 25 slm. The deposition gas exposure and etching gas exposure cycles were repeated 50 times to form an epitaxially grown silicon-containing layer on the exposed monocrystalline portion of the substrate. The silicon-containing epitaxial layer had a thickness of about 1800 mm 3.

Example 14 Selective Epitaxy of Silicon Carbon Doped with P and Etched with Cl ₂ -The substrate was placed in a process chamber maintained heated to 550 ° C. The treatment chamber was maintained at a pressure of about 15 Torr. The substrate surface was then exposed to a flow of deposition gas comprising silane with a flow rate of 100 sccm, methylsilane with a flow rate of 1 sccm, phosphine with a flow rate of 3 sccm, and nitrogen with a flow rate of 25 slm for 8 seconds. The substrate was exposed to an etching gas containing chlorine gas having a flow rate of 20 sccm and nitrogen having a flow rate of 25 slm for 10 seconds. The deposition gas exposure and the exposure cycle of the etching gas were repeated 80 times to form an epitaxially grown silicon-containing layer on the exposed monocrystalline portion of the substrate. The silicon-containing epitaxial layer had a thickness of about 1600 mm 3.

Example 15 Selective Epitaxy of Silicon Carbon Doped with P and Etched with Cl ₂ -The substrate was placed in a process chamber maintained heated to 550 ° C. The treatment chamber was maintained at a pressure of about 15 Torr. The substrate surface was then exposed to a flow of deposition gas comprising silane with a flow rate of 100 sccm, phosphine with a flow rate of 3 sccm and nitrogen with a flow rate of 25 slm for 7 seconds. The substrate was exposed to a flow of a second deposition gas containing methylsilane having a flow rate of 5 sccm and nitrogen having a flow rate of 25 slm for 7 seconds. The substrate was then exposed to an etching gas comprising chlorine gas with a flow rate of 20 sccm and hydrogen with a flow rate of 25 slm for 10 seconds. The deposition gas exposure and the exposure cycle of the etching gas were repeated 80 times to form an epitaxially grown silicon-containing layer on the exposed monocrystalline portion of the substrate. The silicon-containing epitaxial layer had a thickness of about 1800 mm 3.

silicon Epitaxial film  While forming HCl  And / or Cl ₂ Use of

As disclosed, the inventors have found that the use of Cl ₂ as an etchant gas during the silicon epitaxial film formation process leads to poor surface morphology of the silicon epitaxial film formed. Without wishing to be bound by any particular theory, it is believed that Cl ₂ excessively attacks the silicon epitaxial film surface to form pitting and the like. The use of Cl ₂ has been found to be particularly problematic when the silicon epitaxial film contains carbon.

In one embodiment of the invention, Cl ₂ and HCl are used during the etching step of the silicon epitaxial film formation process. The presence of HCl has been shown to reduce the aggressiveness of Cl ₂ even with reduced substrate temperatures (eg, up to about 600 ° C.) where small amounts of HCl can degrade. In addition, during the AGS process, HCl may continue to flow (eg, to improve surface morphology) during the deposition and etching steps of the process.

시스템 및 Poly Gen

시스템이 있으며, 이들은 캘리포니아 산타클라라에 위치된 어플라이드 머티리얼스사로부터 입수가능하다.5 is a flowchart of a first method 500 of using Cl ₂ while forming a silicon epitaxial film. Referring to FIG. 5, method 500 begins at step 501. In step 502, the substrate is placed in a process chamber (not shown) configured to form an epitaxial film. The process chamber may include any conventional epitaxial film chamber configured to form epitaxial films on one or more substrates. Other epitaxial film chambers and / or systems may be used, but exemplary epitaxial film chambers include Epi Centura.

System and Poly Gen

There are systems, and these are available from Applied Materials, Inc., located in Santa Clara, California.

After placement in the process chamber, the substrate is heated to the desired substrate and / or process temperature. In one or more embodiments of the present invention, substrates and / or process temperatures below 700 ° C. may be used to improve carbon integration in any silicon epitaxial layer formed in the process chamber. In certain embodiments, substrate and / or process temperature ranges between about 550 and 650 ° C. may be used, and in other examples, substrate and / or process temperature ranges below about 600 ° C. may be used. Other substrate and / or process temperatures may be used, including substrate and / or process temperatures of 700 ° C. or higher.

After the desired substrate and / or process temperature is achieved, in step 503 the substrate is exposed to at least a silicon source to form a silicon epitaxial film on the substrate. For example, the substrate may be exposed to a silicon source such as silane, a carrier gas such as nitrogen, a dopant source such as phosphorus or boron or the like. Any other suitable silicon source, carrier gas, dopant source or other gas may be used, such as a carbon source, germanium source or any of the gases disclosed above. During the epitaxial film formation process, the epitaxial layer may be formed on any monocrystalline surface of the substrate, and the polycrystalline layer is on any polycrystalline layer and / or any amorphous layer present on the substrate (as previously described). Can be formed on.

In step 504, the substrate is exposed to HCl and Cl ₂ to form a silicon epitaxial film and / or any other films formed on the substrate during step 503 (eg, a polycrystalline or amorphous layer present on the substrate). Polycrystalline silicon formed on the substrate) is etched. Note that the epitaxial film formed on the monocrystalline surface of the substrate is etched slower than any other films formed during step 503.

Even at reduced substrate and / or process temperatures (eg, up to about 600 ° C.) where small amounts of HCl are degraded, the presence of HCl during etching can reduce the aggressiveness of Cl ₂ . In one or more embodiments, a substantially higher flow rate of HCl may be used compared to Cl ₂ . For example, in one or more embodiments, an HCl flow rate of about 6 to 10 times the flow rate of Cl ₂ is used (a larger or smaller ratio of HCl / Cl ₂ may be used). In certain embodiments, a nitrogen carrier gas at an HCl flow rate of about 300 sccm, a Cl ₂ flow rate of about 30-50 sccm and a flow rate of about 10-50 slm (eg, about 20-25 slm) may be used. Other flow rates / ratios may be used.

After etching, the process chamber may be purged with nitrogen and / or other to remove any Cl ₂ and / or any other unwanted species / byproducts (eg, for about 20 seconds or for any other suitable time period). Inert gas). Then, in step 505, a determination is made whether the epitaxial film formed on the substrate is the desired thickness. For example, the thickness of the epitaxial film may be measured or estimated based on the process time and / or other parameters used during steps 503 and / or 504. If the film is the desired thickness, the method 500 ends at step 506; If not, the method 500 returns to step 503 where further deposition (step 503) and etching step 504 are performed on the substrate. Steps 503 and 504 can be repeated until the desired film thickness is achieved.

By using both HCl and Cl ₂ during step 504, the advantages of using Cl ₂ as the primary etchant (eg, lower substrate and / or process temperature treatment, better carbon integration, etc.) are achieved during method 500. It can be implemented without deteriorating the surface morphology of the formed epitaxial films.

시스템 및 Poly Gen

시스템이 있으며, 이들은 캘리포니아 산타클라라에 위치된 어플라이드 머티리얼스사로부터 입수가능하다.6 is a flowchart of a second method 600 of using Cl ₂ while forming a silicon epitaxial film. With reference to FIG. 6, the method 600 begins at step 601. In step 602, the substrate is placed in a process chamber (not shown) configured to form epitaxial films. The process chamber may include any conventional epitaxial film chamber configured to form epitaxial films on one or more substrates. Other epitaxial film chambers and / or systems may be used, but exemplary epitaxial film chambers include Epi Centura.

System and Poly Gen

There are systems, and these are available from Applied Materials, Inc., located in Santa Clara, California.

After placement in the process chamber, the substrate is heated to the desired substrate and / or process temperature. In one or more embodiments of the present invention, substrates and / or process temperatures below 700 ° C. may be used to improve carbon integration in any silicon epitaxial layer formed in the process chamber. In certain embodiments, substrate and / or process temperature ranges between about 550 and 650 ° C. may be used, and in other examples, substrate and / or process temperature ranges below about 600 ° C. may be used. Other substrate and / or process temperatures may be used, including substrate and / or process temperatures of 700 ° C. or higher.

After the desired substrate and / or process temperature is achieved, in step 603, the substrate is exposed to at least a silicon source and HCl to form a silicon epitaxial film on the substrate. For example, the substrate can be exposed to a silicon source such as silane or disilane, carrier gas such as HCl, and nitrogen. Dopant sources such as phosphorus or boron, carbon sources, germanium sources, etc. may be used (any other suitable source and / or gas may be used). During the epitaxial film formation process, the epitaxial layer is formed on any monocrystalline surface of the substrate while the polycrystalline layer is formed on any amorphous and / or any polycrystalline layer present on the substrate (as previously described). Can be. The presence of HCl during the formation of the silicon epitaxial film can enhance the silicon epitaxial film deposition selectivity compared to any other films (e.g. polycrystalline layers) formed on the substrate and improve the epitaxial film surface morphology. Can be.

In at least one embodiment, with a nitrogen carrier gas at a flow rate of about 50-150 sccm for silane (or about 10-40 sccm for disilane) and about 10 slm-50 slm (eg, about 20-25 slm) An HCl flow rate of about 300 sccm can be used. Larger or smaller HCl, silicon source and / or carrier gas flow rates may be used.

In step 604, the substrate is exposed to HCl and Cl ₂ to form an epitaxial film and / or any other films formed on the substrate during step 603 (eg, on polycrystalline or amorphous layers present on the substrate). Polycrystalline silicon) is etched. Note that the epitaxial film formed on the monocrystalline surface of the substrate is etched slower than any other films formed during step 603. As disclosed, the presence of HCl has been shown to reduce the aggressiveness of Cl ₂ , even with reduced substrate and / or process temperatures (eg, up to about 600 ° C.) where small amounts of HCl can degrade.

In at least one embodiment, substantially higher flow rates of HCl can be used compared to Cl ₂ . For example, in at least one embodiment, HCl at a flow rate of about 6 to 10 times Cl ₂ is used (higher or smaller HCl / Cl ₂ ratios may be used). In one specific embodiment, an HCl flow rate of about 300 sccm, a Cl ₂ flow rate of about 30-50 sccm and a nitrogen carrier gas flow rate of about 20-25 slm may be used (other flow rates may be used).

After etching, the process chamber may be purged with nitrogen and / or other to remove any Cl ₂ and / or any other unwanted species / byproducts (eg, for about 20 seconds or for any other suitable time period). Inert gas). Then, in step 605, a determination is made whether the epitaxial film formed on the substrate is the desired thickness. For example, the thickness of the epitaxial film may be measured or estimated based on the process time and / or other parameters used during steps 603 and / or 604. If the film is the desired thickness, the method 600 ends at step 606; If not, the method 600 returns to step 603 where further deposition (step 603) and etching step 604 are performed on the substrate. Steps 603 and 604 may be repeated until the desired film thickness is achieved.

As described above, by using both HCl and Cl ₂ during step 604, the advantages of using Cl ₂ as the primary etchant (eg, lower substrate and / or process temperature treatment, better carbon integration, etc.) It can be implemented without deteriorating the surface morphology of the epitaxial films formed during the method 600. In addition, the use of HCl during step 603 may assist in the formation of silicon epitaxial films with respect to the formation of any other films (eg, polycrystalline silicon) on the substrate. The same or different HCl flow rates may be used in steps 603 and 604.

시스템 및 Poly Gen

시스템이 있으며, 이들은 캘리포니아 산타클라라에 위치된 어플라이드 머티리얼스사로부터 입수가능하다.7 is a flow chart of a third method of using Cl ₂ while forming a silicon epitaxial film. With reference to FIG. 7, method 700 begins at step 701. In step 702 the substrate is placed in a process chamber (not shown) configured to form epitaxial films. The process chamber may include any conventional epitaxial film chamber configured to form epitaxial films on one or more substrates. Other epitaxial film chambers and / or systems may be used, but exemplary epitaxial film chambers include Epi Centura.

System and Poly Gen

There are systems, and these are available from Applied Materials, Inc., located in Santa Clara, California.

After placement in the process chamber, the substrate is heated to the desired substrate and / or process temperature. In one or more embodiments of the present invention, substrates and / or process temperatures below about 700 ° C. may be used to improve carbon integration in any silicon epitaxial layer formed in the process chamber. In certain embodiments, substrate and / or process temperature ranges between about 550 and 650 ° C. may be used, and in other examples, substrate and / or process temperature ranges below about 600 ° C. may be used. Other substrate and / or process temperatures may be used, including substrate and / or process temperatures of 700 ° C. or higher.

After the desired substrate and / or process temperature is achieved, in step 703, the substrate is exposed to at least a silicon source and a carbon source such that a carbon-containing silicon epitaxial film is formed on the substrate. For example, the substrate may be exposed to a silicon source such as silane or disilane, a carbon source such as methane, a carrier gas such as nitrogen, or the like. Dopant sources such as phosphorus or boron, germanium sources and the like may be used (any other suitable source and / or gas may be used). During the epitaxial film formation process, the epitaxial layer is formed on any monocrystalline surface of the substrate while the polycrystalline layer is formed on any amorphous and / or any polycrystalline layer present on the substrate (as previously described). Can be.

In at least one embodiment, a carbon source at a flow rate of about 1-5 sccm for methane is a silicon source at a flow rate of about 50-150 sccm (or about 10-40 sccm for a disilane) and a nitrogen carrier source at a flow rate of about 20-25 slm (Larger or smaller carbon source, silicon source and / or carrier gas flow rates may be used). If desired, HCl may be introduced.

The carbon containing epitaxial film is, for example, about 10 to about 1600 ohms thick, although other thicknesses may be used. For example, a deposition time of about 1 second to about 300 seconds and about 10 seconds in one or more embodiments may be used.

In step 704, the carbon-containing silicon epitaxial film is encapsulated into an encapsulation film. For example, the encapsulation film can be formed by exposing the substrate to a carrier source, such as nitrogen and a silicon source, such as silane or disilane, such that a silicon epitaxial film (without a carbon source) is formed over the carbon-containing silicon epitaxial film. . Substrate and / or process temperatures similar to or different from the substrate and / or process temperatures of step 703 may be used. The presence of the encapsulation film on the carbon-containing silicon epitaxial film can reduce the carbon-chlorine interaction and improve the surface morphology of the carbon-containing silicon epitaxial film (during etching). For example, because many carbon sources are rich in hydrogen, the silicon surface exposed to the carbon source can be terminated with significant hydrogen. This hydrogen terminated surface may react poorly with chlorine during etching.

In at least one embodiment, the silicon epitaxial film can be used as an encapsulation film, a silicon source at a flow rate of about 50-150 sccm for silane (or a flow rate of about 10-40 sccm for disilane) and a nitrogen carrier at a flow rate of about 20-25 slm It can be formed by flowing gas (greater or smaller silicon source and / or carrier gas flow rates can be used). In addition, HCl may flow as disclosed above with reference to FIG. 6.

The first silicon epitaxial film may have a thickness of about 2 ohms to about 500 ohms, but other thicknesses may be used. For example, a deposition time of about 1 second to about 100 seconds, and about 5 seconds in one or more embodiments may be used.

In step 705, the substrate is exposed to Cl ₂ and any other films and / or encapsulation films formed during step 704 are etched (eg, polycrystalline and / or amorphous in which polycrystalline silicon is present on the substrate). Or monocrystalline silicon is formed on the carbon-containing silicon epitaxial film). For example, in at least one embodiment, the substrate may be exposed to Cl _{2 at a} flow rate of about 30-50 sccm and nitrogen carrier gas at a flow rate of about 20-25 slm (greater or smaller Cl ₂ and / or nitrogen carrier gas flow rates). Can be used). HCl may flow as disclosed above with reference to FIG. 6. Other etchant and / or carrier gases may be used.

After etching, the process chamber may be purged with nitrogen and / or other to remove any Cl ₂ and / or any other unwanted species / byproducts (eg, for about 20 seconds or for any other suitable time period). Inert gas). Then, in step 706, a determination is made whether the epitaxial film formed on the substrate is the desired thickness. For example, the thickness of the epitaxial film can be measured or estimated based on the process time and / or other parameters used during steps 703 and / or 704 and / or 705. If the film is the desired thickness, the method 700 ends at step 707; Otherwise, the method 700 returns to step 703 where further deposition (step 703), encapsulation step (step 704) and etching step (step 705) are performed on the substrate. Steps 703, 704 and / or 705 may be repeated until the desired film thickness is achieved.

시스템 및 Poly Gen

시스템이 있으며, 이들은 캘리포니아 산타클라라에 위치된 어플라이드 머티리얼스사로부터 입수가능하다.8 is a flowchart of a fourth method 800 of using Cl ₂ during silicon epitaxial film formation. With reference to FIG. 8, the method 800 begins at step 801. In step 802, the substrate is placed in a process chamber (not shown) configured to form epitaxial films. The process chamber includes any conventional epitaxial film chamber configured to form epitaxial films on one or more substrates. Other epitaxial film chambers and / or systems may be used, but exemplary epitaxial film chambers include Epi Centura.

System and Poly Gen

There are systems, and these are available from Applied Materials, Inc., located in Santa Clara, California.

After placement in the process chamber, the substrate is heated to the desired substrate and / or process temperature. In one or more embodiments of the present invention, substrates and / or process temperatures below about 700 ° C. may be used to improve carbon integration within any silicon epitaxial layer formed in the process chamber. In certain embodiments, substrate and / or process temperature ranges between about 550 and 650 ° C. may be used, and in other examples, substrate and / or process temperature ranges below about 600 ° C. may be used. Other substrate and / or process temperatures may be used, including substrate and / or process temperatures of 700 ° C. or higher.

After the desired substrate and / or process temperature is achieved, at step 803, the substrate is exposed to at least a silicon source such that a first silicon epitaxial film is formed on the substrate. For example, the substrate may be exposed to a silicon source such as silane or disilane, a carrier gas such as nitrogen, or the like. Dopant sources such as phosphorus or boron, germanium sources and the like may be used (any other suitable source and / or gas may be used). During the epitaxial film formation process, the epitaxial layer is formed on any monocrystalline surface of the substrate while the polycrystalline layer is formed on any amorphous and / or any polycrystalline layer present on the substrate (as previously described). Can be. HCl may also flow as disclosed above with reference to FIG. 6.

The first silicon epitaxial film may be formed, for example, by flowing a silicon source at a flow rate of about 50-150 sccm (or a flow rate of about 10-40 sccm for a disilane) and a nitrogen carrier gas at a flow rate of about 20-25 slm for the silane. Larger or smaller silicon source and / or carrier gas flow rates may be used. HCl may also flow as disclosed above with reference to FIG. 6.

In at least one embodiment, the first silicon epitaxial film has a thickness of about 2 ohms to about 100 ohms, and other thicknesses may be used. For example, a deposition time of about 1 second to about 100 seconds, and about 5 seconds in one or more embodiments may be used.

After the first silicon epitaxial film is formed, in step 804, the substrate is exposed to at least the silicon source and the carbon source such that a carbon-containing silicon epitaxial film is formed over the first silicon epitaxial film. For example, the substrate is exposed to a silicon source such as silane or disilane, a carbon source such as methane, and a carrier gas such as nitrogen. Dopant gases such as phosphorus, boron, germanium sources and the like may be used (any other suitable source and / or gas may be used). During the epitaxial film formation process, the carbon containing epitaxial layer is formed on any monocrystalline surface of the substrate while the polycrystalline layer is on any polycrystalline layer and / or any amorphous layer present on the substrate (as previously described). Is formed.

In at least one embodiment, a carbon source at a flow rate of about 1-5 sccm for methane is a silicon source at a flow rate of about 50-150 sccm for silane (or a flow rate of about 10-40 sccm for disilane) and a nitrogen carrier at a flow rate of about 20-25 slm Larger or smaller silicon source and / or carrier gas flow rates may be used with the gas. HCl may flow if desired.

The carbon-containing epitaxial film may, for example, have a thickness from about 2 ohms to about 100 ohms, and other thicknesses may be used. For example, a deposition time of about 1 second to about 50 seconds, and about 10 seconds in one or more embodiments may be used.

After the carbon-containing silicon epitaxial film is formed, in step 805 the substrate is exposed to at least a silicon source (without a carbon source) such that a second silicon epitaxial film is formed on the substrate over the carbon-containing silicon epitaxial film. For example, the substrate may be exposed to a silicon source such as silane or disilane, and a carrier source such as nitrogen. Dopant sources such as phosphorus or boron, germanium sources and the like may be used (any other suitable source and / or gas may be used). The presence of a second silicon epitaxial film on the carbon-containing silicon epitaxial film can reduce the interaction of carbon and chlorine (and / or hydrogen) in the carbon-containing silicon epitaxial film (formed during step 804). . In addition, HCl may flow as described above with reference to FIG. 6.

The second silicon epitaxial film can be formed, for example, by flowing a silane source at a flow rate of about 50-150 sccm (or a flow rate of about 10-40 sccm for a disilane) and a nitrogen carrier gas at a flow rate of about 20-25 slm. Larger or smaller silicon source and / or carrier gas flow rates may be used. In addition, HCl may flow as described above with reference to FIG. 6.

In one or more embodiments, the second silicon epitaxial film may have a thickness of about 2 ohms to about 100 ohms, and other thicknesses may be used. For example, a deposition time of about 1 second to about 100 seconds, and about 5 seconds in one or more embodiments may be used.

In step 806, the substrate is exposed to Cl ₂ to etch any other films and / or at least a second silicon epitaxial film formed during step 805 (e.g., polycrystalline silicon is present on the substrate Formed on the amorphous and / or amorphous layer and monocrystalline silicon is formed on the carbon-containing silicon epitaxial film). For example, in at least one embodiment, the substrate may be exposed to a Cl ₂ and 20 slm flow rate nitrogen carrier gas at a flow rate of about 30-50 sccm (greater or smaller Cl ₂ and / or nitrogen carrier gas flow rates may be used. have). In addition, HCl may flow as described above with reference to FIG. 5.

Upon etching, the process chamber is free of any Cl ₂ from the chamber. And / or purged to remove any other unwanted species / by-products (eg, with nitrogen and / or other inert gas for about 20 seconds or any other suitable time period). Then, in step 807, a determination is made as to whether the epitaxial film formed on the substrate is the desired thickness. For example, the thickness of the epitaxial film can be measured or estimated based on the process time and / or other parameters used during steps 803 and / or 804 and / or 805. If the film is the desired thickness, the method 800 ends at step 808; If not, the method 800 returns to step 803 where further deposition (steps 803-805) and additional etching steps (step 806) are performed on the substrate. Steps 703, 704, 805 and / or 806 may be repeated until the desired film thickness is achieved.

Methods 700 and / or 800 (FIGS. 7 and 8) can be used to encapsulate another type of silicon epitaxial film (in addition to carbon-containing epitaxial films). For example, additional element sources, such as sources of germanium, boron, phosphorus, etc., may be used during step 703 (FIG. 7) or step 804 (FIG. 8) to form additional element-containing silicon epitaxial films. The next additional element containing silicon epitaxial film is then referred to with reference to FIGS. 7 and 8 (eg, to prevent exposure of the additional element containing silicon epitaxial film to Cl ₂ during step 705 or step 806). It may be encapsulated during step 704 or step 805 in a manner similar to that disclosed.

9 is a block diagram of an exemplary epitaxial film formation system 900 provided in accordance with the present invention. With reference to FIG. 9, system 900 includes an epitaxial chamber 902 that includes a substrate support 904 and at least one heating module 906. The substrate support 904 is configured to support the substrate 908 during the formation of the epitaxial film in the epitaxial chamber 902, and the heating module 906 during the formation of the epitaxial film in the epitaxial chamber 902. Configured to heat the substrate 908. One or more heating modules, and / or other heating module arrangements may be used. Heating module 906 may include, for example, a lamp array or any other suitable heating source and / or member.

System 900 may also be coupled to gas supply 910 and exhaust system 912 coupled to epitaxial chamber 902 and to epitaxial chamber 902, gas supply 910 and / or exhaust system 912. Controller 914 to be included. Gas supply 910 may include a source and / or delivery system for any source, carrier, etchant, dopant or other gases used by epitaxial chamber 902. Exhaust system 912 may include any suitable system for evacuating waste gases, reaction byproducts, and the like from chamber 902 and may include one or more vacuum pumps.

The controller 914 is one or more microprocessors and / or microcontrollers, dedicated hardware, combinations thereof that can be used to control the operation of the epitaxial chamber 902, the gas supply 910 and / or the exhaust system 912. And the like. In at least one embodiment, the controller 914 may be configured to use the computer program code 916 to control the operation of the system 900. For example, the controller 914 can perform or initiate any one or more steps of the methods / processes disclosed herein, including the methods 500, 600, 700, 800 of FIGS. 5-8. . Any computer program code that performs and / or initiates these steps may be implemented in a computer program product. Each computer program product disclosed herein may be held by a computer readable medium (eg, carrier wave signal, floppy disk, compact disk, DVD, hard drive, random access memory, etc.).

The use of both Cl ₂ and HCl in accordance with the present invention can be used during selective Si-containing deposition processes, such as co-flow processes (selective epitaxial processes in which deposition and etching reactions occur simultaneously). . In addition, the use of both Cl ₂ and HCl according to the invention can be used to treat the surface of the Si-containing film or to form source / drain recess regions of a metal oxide semiconductor field effect transistor (MOSFET) via silicon etching. Can be. An exemplary surface treatment process and / or a process of forming a source / drain recess region of a MOSFET that may be useful with a combined Cl ₂ / HCl flow in accordance with the present invention, filed Jan. 31, 2005, referenced herein. , US patent application Ser. No. 11 / 047,323 (dock number 9793). During the AGS process, the etching and deposition steps can be performed at different temperatures. For example, the deposition temperature can be lower than the etch temperature to increase substituted carbon integration. In certain embodiments, substrate temperatures below about 650 ° C. may be used during deposition and substrate temperatures above about 650 ° C. may be used during etching. Although so far directed to embodiments of the invention, other additional embodiments of the invention may be devised without departing from the basic scope, and spirit, of the invention as defined by the following claims.

Claims (41)

As a method of forming an epitaxial film on a substrate, (a) providing a substrate; (b) exposing the substrate to at least a silicon source such that an epitaxial film is formed on at least a portion of the substrate; And (c) exposing the substrate to HCl and Cl ₂ such that the epitaxial film and any other films formed during step (b) are etched. Larger HCl flow rate is used compared to Cl ₂ flow rate? Method comprising forming an epitaxial film, comprising. The method of claim 1, further comprising repeating steps (b) and (c) at least once. The method of claim 1, exposing the substrate to an additional element source during step (b). The method of claim 3, wherein And wherein the additional element source comprises one of a carbon source and a germanium source. The method of claim 3, wherein Wherein the additional element source comprises a boron or phosphorus source. The method of claim 1, (b) flowing HCl during the step, further comprising forming an epitaxial film. The method of claim 6, using the same HCl flow rate during steps (b) and (c). The method of claim 1, (c) using an HCl flow rate of 6 to 10 times the Cl ₂ flow rate during step (c). The method of claim 1, wherein step (b) (i) exposing the substrate to a carbon source such that a carbon-containing silicon epitaxial film is formed; And (ii) encapsulating the carbon-containing silicon epitaxial film Method comprising forming an epitaxial film, comprising. The method of claim 9, Encapsulating the carbon-containing silicon epitaxial film comprises exposing the substrate to the silicon source without the carbon source such that a silicon epitaxial film is formed over the carbon-containing silicon epitaxial film. . The method of claim 1, wherein step (b) (i) exposing the substrate to the silicon source without a carbon source such that a first silicon epitaxial film is formed; (ii) exposing the substrate to the carbon source and the silicon source such that a carbon-containing silicon epitaxial film is formed over the first silicon epitaxial film; And (iii) exposing the substrate to the silicon source without the carbon source such that a second silicon epitaxial film is formed over the carbon-containing silicon epitaxial film. Method comprising forming an epitaxial film, comprising. The method of claim 11, wherein (ii) using the processing time of steps (i) and (iii) which are half of the processing time of step (ii). As a method of forming an epitaxial film on a substrate, (a) providing a substrate; (b) exposing the substrate to a silicon source and a carbon source such that a carbon containing silicon epitaxial film is formed; (c) the carbon-containing silicon epitaxial film, wherein the carbon-containing silicon epitaxial film is formed on the Cl ₂ Encapsulating with an encapsulation film configured to prevent exposure; And (d) exposing the substrate to Cl ₂ so that the encapsulation film is etched; The encapsulation film prevents the carbon-containing silicon epitaxial film from being exposed to Cl ₂ ? Method comprising forming an epitaxial film, comprising. The method of claim 13, further comprising repeating steps (b) to (d) at least once. As a method of forming an epitaxial film on a substrate, (a) providing a substrate; (b) exposing the substrate to a silicon source and an additional element source such that an additional element-containing silicon epitaxial film is formed; (c) the additional element-containing silicon epitaxial film is attached to Cl ₂ . Encapsulating with an encapsulation film configured to prevent exposure; And (d) exposing the substrate to Cl ₂ so that the encapsulation film is etched; The encapsulation film prevents the additional element-containing silicon epitaxial film from being exposed to Cl ₂ ? Method comprising forming an epitaxial film, comprising. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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